item: the thing (product, event, business, etc) being reviewed. This property contains these subproperties (which all come from hCard):

o fn: the formatted name of the thing being reviewed (e.g., if the thing being reviewed is a book, then fn is the book title; if the thing being reviewed is a movie then fn is the name of the movie).
o url: the URL to the thing being reviewed (e.g., if the thing being reviewed is a company that paints houses, then url is the URL to their web site).
o photo: a URL to the thing being reviewed (e.g., if the thing being reviewed is a book, then photo is the URL to a photo of the book).